Furan 2- methyl-3-ethoxycarbonyl

Furan 2-[2-(bzw. 3 bzw.4)-Chlor-phenyl]-3,4-dihydroxy-5-imino-2,5-dihydro- VI/2, 698 f. Isocyanat (2-Chlor-l-phenyl-ethoxycarbonyl)- E4, 1244 (Cl —CO —NCO +- Oxiran) Quinolin 8-Chlor-4-methyl-2,5,6-trihydroxy- VI/lc, 624... 

The following examples report the published orientation, but the reader will keep in mind the possibility of isomerization. Methyl dimethylaminopro-piolate (Me2NC=CC02Me) and ethyl azidoformate, stirred in tetrahydro-furan, gave 4-dimethylamino-3-ethoxycarbonyl-5-methoxycarbonyltriazole (25°C, 3 hr, 70%). l-Dimethylaminobut-l-yn-3-one similarly gave 5-acetyl-4-dimethylamino-3-ethoxycarbonyltriazole (80%) (69HCA2641). 

Als Enol-ether von 1,3-Dicarbonyl-Verbindungen und 3-Oxo-alkansaure-estern reagieren 5-Aryl-2-(ethoxycarbonyl-methylen)-4-methyl-3-oxo-2,3-dihydro-furane mil 70%iger Hy-drazin-Hydrat-Losung zu 3(5),3 (5 )-Bi-lH-pyrazolylen988. 

A soln. of the startg. sulfonium salt in abs. ethanol added dropwise with icecooling to a stirred mixture of ethyl acetoacetate and Na-ethoxide in abs. ethanol, and the product isolated after 5 hrs. -> 9-ethoxycarbonyl-8-methyl-7-oxabicyclo-[4.3.0]-8-nonen-5-one. Y 91-98%. F. e. s. T. Mukaiyama, T. Adadii, and T. Kumamoto, Bull. Chem. Soc. Japan 44, 3155 (1971) furans from 2-acetylenesulfo-nium salts cf. J. W. Batty, P. D. Howes, and C. J. M. Stirling, Soc. Perkin I 1973, 65. 

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